This is the Castle Creations Griffin 40 FAI Speed Control for brushed motors.
Will only work with brushed motors, will not work with brushless.

FEATURES: Microprocessor controlled
Low resistance (.0014 ohms)
High rate (2800Hz) switching (PWM)
Up to 40A continuous current (with proper air flow)
Dual Battery Eliminator Circuit (BEC) provides power
to receiver and servos- eliminates separate receiver battery
Six to eight cells with three or four micro servos
Up to ten cells with two micro servos
Audible signal confirms system is armed
Dynamic braking ensures folding props fold properly
Sixteen cells MAX with BEC disabled
Auto motor cutoff with reset
Adjusts to any transmitter
Safe power on arming program ensures motor will not accidentally
turn ON
Low torque soft start prevents damage to fragile gearboxes
Auto shut down when signal is lost or radio interference becomes
severe
Rugged surface mount construction

INCLUDES: One Griffin 40 ESC
One Schottky diode
Instruction sheets

SPECS: Length: 2.0" (49mm)
Width: 3.5" (86mm)
Height: 0.5" (12mm)
Wire Length: Motor end 5.0" (127mm) Rx Connector: 12" (305mm)
Battery end: 5.0" (127mm)